Why pressure increases as a gas is compressed into a smaller volume?

Pressure usually increases as a gas is compressed into a smaller volume. A sample of gas in a container creates pressure by colliding with the wall of the container. The gas particles move about randomly and occupies all the space in the container. If the sample of gas is compressed into a smaller volume, the pressure of the gas will be increased because the gas particles has less space to occupies and they will collide more frequently with the wall of the container.